Radio frequency identification (RFID) system technology is well known in the art. One or more forms of electronic devices, typically small in size, are available for use with these technologies. For example, common examples are found in passive RFID tags, as well as active RFID transponders. In the context of this disclosure the terms ‘passive RFID device’ or ‘passive RFID tag’ will include electronic devices that typically do not truly transmit RF signals, but instead reflect or backscatter transmissions generated by a proximate RFID reader or interrogator. In addition, ‘active RFID devices’ and ‘active RFID tags’, will be defined as electronic devices that actually may transmit RF signals (typically in response to received RF signals). These active devices are also known as transponders (i.e., a transmitter+a responder). When referring collectively to both passive and active RFID tags, the term ‘electronic device’ will be employed. As such, the term electronic device, as employed within the context of this disclosure, is to be broadly defined.
It may be noted that a significant difference between passive and active RFID devices is found in their operational ranges. Passive tags, are desirable due to their small size, low cost, and very long operating life. However, as indicated in FIG. 1A, a passive RFID tag 30a may have a very limited range when being interrogated by an RF signal radiated from RF antenna 42 of RFID interrogator 40. As such, it is common that a passive RFID tag 30a must be moved quite close to an RF antenna of an interrogator's reading head. For example, it is not uncommon for a passive tag to need to be from 0 to 2 centimeters away from a surface of a reading head to function properly. For a given application, having to get that close to the asset of interest may be difficult, if not impossible.
In contrast, the active RFID transponder 30b, as shown in FIG. 1B, may be read using RFID interrogator 40 over a range of multiple centimeters to multiple meters, or more. However, active transponders generally include a battery, and are larger and more expensive than their passive counterparts. This results in a significant cost difference between the low cost passive RFID tags, and the more complicated active RFID transponder devices. When considering a system such as an asset management system, wherein thousands upon thousands of assets are to be inventoried, the cost of the asset identifying means employed, such as RFID tags, can be an important cost factor.
As such, it would be desirable to provide a means to increase the operational distance over which a low cost electronic device, such as a passive RFID tag, can be interrogated (e.g., read or written), while at the same time not adding significant costs. It would be most desirable for the means to be a passive, low cost arrangement that may be employed without having to substantially modify either the electronic device (which is fixable to an asset) or the antenna portion of a suitable RFID reader or interrogator.
A number of other characteristics, advantages, and or associated novel features of the present invention, will become clear from the description and figures provided herein. Attention is called to the fact, however, that the drawings are illustrative only. In particular, the embodiments included and described, have been chosen in order to best explain the principles, features, and characteristics of the invention, and its practical application, to thereby enable skilled persons to best utilize the invention and a wide variety of embodiments providable that are based on these principles, features, and characteristics. Accordingly, all equivalent variations possible are contemplated as being part of the invention, limited only by the scope of the appended claims.